1. Technical Field
Embodiments of the present invention relate to a recording apparatus and a recording method that perform recording on a recording medium by performing scanning of a recording unit and insertion of linefeeds that relatively move the recording unit and the recording medium in the direction crossing the scanning direction, such as a lateral recording method and a serial recording method.
2. Related Art
For example, a printing apparatus (recording apparatus), such as a serial-type printer and a lateral scan-type printer, prints a document or an image by ejecting ink droplets from the nozzle of a recording head disposed on a carriage during each movement or pass of the carriage in the main scanning direction.
For example, printing apparatuses including a recording unit equipped with a plurality of recording heads (printing heads) are disclosed in JP-A-2004-25551 and JP-A-2010-142981. The recording heads are arranged in two lines or four lines, for example, in a zigzag pattern, in the recording unit. In the printing apparatus described in JP-A-2004-25551, a plurality of printing heads and driving control units corresponding to one or more of a predetermined number of printing heads are mounted on a carriage. A plurality of data processing units that transmit data to the driving control units, respectively, are mounted on the main body of the printing apparatus. A predetermined number of printing heads, one driving control unit, and one data processing unit are connected to a main control unit. The main control unit performs main control for reciprocating the carriage. In the printing apparatus, a plurality of circuit sets each of which is composed of one driving control unit and one data processing unit for a predetermined number of printing heads is provided, such that the process load per data processing unit is small.
Further, for example, printing apparatuses that print a composite image implemented by fixing data of a fixing image (common image) which is the same each time and variable data of a variable image which changes each time are disclosed in JP-A-2001-301248 and JP-A-2010-181999.
For example, as the number of recording heads increases, it may be possible to consider a configuration provided with two or more main control units themselves and divisionally controlling a plurality of recording heads with the two or more main control units (control units). In this case, the main control units are necessary to be synchronized when controlling the corresponding recording heads, respectively. For example, in the case with two main control units, one of them is a master (master side controller) and the other is a slave (slave side controller) and printing is controlled at the time when all the controllers are prepared to start while the master side controller communicates with the slave side controller to be synchronized.
FIG. 13 shows an example of a printer divisionally controlling a plurality of recording heads mounted on the type of recording unit, with two controllers (control units). As shown in FIG. 13, the printer includes two controllers C1 and C2 divisionally controlling a plurality of recording heads 201A and 201B mounted on a recording unit 200, for example. The recording heads 201A and 201B are arranged in two lines at two different positions in a main scanning direction X (left-right direction in the figure) in a zigzag pattern. Since the recording head in the two lines have different ink ejection timing, it is preferable that the master side controller C1 control the recording heads 201A in the right line which have the same ejection timing and the slave side controller C2 control the recording heads 201B in the left line which have the same ejection timing.
The data for printing a plurality of frame images shown in FIG. 13 is common fixed data SD and variable data VD with variable values, such as numbers or symbols, which are provided for the frames, respectively. The printing when a part of an image is variable data, as described above, is particularly called partial variable printing. It is preferable, in the partial variable printing, to share the fixed data SD, and for example, combine the variable data VD changing for each frame into the fixed data SD.
Meanwhile, as shown in FIG. 13, the recording regions (master recording regions) of the recording heads 201A controlled by the master side controller C1 and the recording regions (slave recording regions) of the recording heads 201B controlled by the slave side controller C2 are alternately arranged of one recording head each in the sub-scanning direction Y. Therefore, several boundary lines are shown in each recording head. For example, when the number of the recording heads is G, G−1 boundary lines L are shown for the length of each nozzle line of one recording head in the sub-scanning direction Y. There was a problem in that as the number of boundary lines L increases, as described above, the frequency of the variable data straddling the boundary lines L increases.
When the variable data VD straddles the boundary line L of the master recording region and the slave recording region and the recording control timings of the recording heads 201A and 201B are slightly different between the controllers C1 and C2, a variable image may be printed out of alignment at both sides of the boundary line L. In particular, since the variable image is necessary to be clearly printed, such as a number, a symbol, or a code image (barcode or two-dimensional code), it is difficult to read out the variable image, such as a number, a symbol, or a code image, when the variable image is printed out of alignment at both sides of the boundary line. There is a problem in that the small print misalignment may cause misreading, when reading the variable image on the basis of the result of taking the variable image with a camera or the like.
On the other hand, it is necessary to make the controllers C1 and C2 perform complicated processes or complicate control, or to perform communication of exchanging information for the complicated processes or control between the controllers C1 and C2 or communication for synchronization between the controllers C1 and C2, in order to prevent the print misalignment in the variable image. In this case, the controllers C1 and C2 are provided with extra processes or additional control or high frequency of communication between the controllers C1 and C2. As a result, there may be a problem in that an increase in processing load of the controllers C1 and C2 is caused by them or print throughput is correspondingly decreased.
In detail, when the controllers C1 and C2 generate variable data and the variable data straddles the master and the slave, and when the result of process pass analysis and error diffusion data of the joint is not exchanged, the joint may be shown after printing. That is, the error diffusion process uses the previous (for example, upper or left) data processing result, such that when the slave processes the head of a gap without checking the last process result of the master, matching with the last data of the master is not performed and a line may be shown at the joint after printing. When image process data is exchanged each time between the controllers C1 and C2 of the master and the slave in order to prevent this problem, printing is made very slow because the communication (for example, serial communication) between the controllers C1 and C2 is low.